WASHINGTON--Union activist Cliff Smith once thought of Bernie Sanders as an "obscure" U.S. senator. That changed in August when Smith joined 27,000 people to hear the Democratic White House candidate speak at a Los Angeles sports arena. "The other candidates - they talk in these very calculated, milquetoast, vague ways - they just don't come across as human," said Smith, the business manager for Local 36, a branch of a roofers' union. "He just seems like your next-door neighbour." Sanders' vow to protect American jobs and rein in big corporations has resonated with union workers such as Smith. Sanders, who is challenging Hillary Clinton, the front-runner for the Democratic presidential nomination, has put the courtship of organized labour at the heart of his fight. Reuters interviews with dozens of activists and union leaders reveal an unusual Sanders union strategy that can be summed up in one word: Stall. Rather than pressing for endorsements, the pro-Sanders group Labor for Bernie is asking national unions to at least stay neutral for now. They hope this will buy time for Sanders to convince labour he is electable in the November 2016 presidential election. Sanders' supporters say strong showings in the debates and early primaries will demonstrate his viability and bolster his support. That, in turn, would put him in a stronger position to push for endorsements. Still, said Sander's Iowa state director, Robert Becker, it will be on-the-ground organizing, not national endorsements, that will be crucial in getting workers to take part in the early Iowa and New Hampshire nominating contests. In trying to win over union members, Sanders' supporters argue that he is better able than Clinton to represent labour's positions on issues such as trade and the minimum wage. Union endorsements would give Clinton and Sanders both a symbolic and a practical boost given labour's traditional role in raising money and mobilizing voters for the Democratic Party. The push for labour's support comes as Clinton is feeling more pressure from Sanders. Clinton leads Sanders for the Democratic nomination, 46 percent to 24 percent, in a Reuters/Ipsos rolling five-day poll ending Sept. 4. But Sanders has opened a nine-point lead over Clinton among party supporters in New Hampshire, according to an NBC News/Marist Poll released on Sunday. The survey showed that 41 percent of Democratic voters would back Sanders while 32 percent would cast a vote for Clinton if the poll were held today and Vice President Joe Biden were on the ballot. In July, Sanders had 32 percent support while Clinton had 42 percent backing in the same poll. The Vermont senator is making inroads in Clinton's union support. When she won national endorsements this summer from the American Federation of Teachers and the International Association of Machinists and Aerospace Workers, many rank-and-file members took to Twitter and Facebook to express their dismay and voice support for Sanders. Sanders so far has gotten one national endorsement, from National Nurses United. Over Labor Day weekend, Clinton and Sanders are courting union workers at picnics and parades in Iowa and New Hampshire. They are intensifying their efforts as national unions such as AFSCME, dominated by public-sector workers, prepare for autumn meetings to consider whether to formally endorse one of the Democratic candidates. "I'm looking for additional endorsements as we go forward," Clinton told reporters in Puerto Rico on Friday. "I'm not taking anything for granted. I'm going to work hard to win as much support as I possibly can." Meanwhile, Labor for Bernie is urging AFSCME and other national unions to put the brakes on formal endorsements. Petitions are circulating, including one to the Service Employees International Union, which has 2 million members, urging leaders to stay on the sidelines for now.